How long did the Gold fire last?

It burned between 4 August 2025 and 4 August 2025: 1 day, according to the start date recorded by United States agencies (MTBS / NIFC) and the heat detections seen by satellite.

How much area did it burn?

The official perimeter published by United States agencies (MTBS / NIFC) is 419 hectares (4.2 km²). Other tallies, such as daily incident reports, may give slightly different figures.

Which counties burned?

The fire only entered San Bernardino (414 ha, 0.0 %).

What was the weather like?

During the fire the temperature reached 28.7 °C, humidity dropped to 10 % and gusts hit 56 km/h. The fire danger index (FWI) reached 52, class Extreme.

Where does this data come from?

From the official burnt perimeter of United States agencies (MTBS / NIFC, public domain), NASA FIRMS VIIRS hotspots and the administrative boundaries of United States. It is not an official report.

US · United States · 2025-08-04 → 2025-08-04

Gold Fire, August 2025 San Bernardino

Out · last detection 5 Aug 2025, 20:27 UTC

The fire started on 4 August 2025 in San Bernardino, United States, and satellites saw it burning for 1 day. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 419 hectares, spread across a single county.

It is the 432th largest in California since 2016 (of 442 with a page). Number 321 in United States in 2025, of 327.

Burnt area: 419ha; official perimeter (MTBS / NIFC)
Duration: 1day; 4 Aug 2025 – 4 Aug 2025
Municipalities hit: 1; counties
Started on: 4 Aug; 2025
Heat detections: 84; in a single hotspot: 212 MW
Danger at start: 43; Very high · FWI index
Energy released: 2.3GW; sum of detected power

Play back 5 Aug 2025

HOTSPOTS BY DAY 4 Aug4 Aug

How it evolved, day by day

Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.

The weather it burned in

29°high

56km/h · peak gust

10%lowest humidity

It had gone 15 days without rain (1 mm or more) when it started.

This area had burned before

No earlier perimeters overlap this fire since 2016, when the satellite record begins.

What happened to each town

San Bernardino where it started

414 ha reached on 4 Aug

0.0 %

Burnt area inside each county, from crossing the official perimeter with administrative boundaries. The distance is from the town centre to the nearest fire: staying a kilometre away does not mean it reached the houses.

The weather day by day

ECMWF ERA5 reanalysis at the fire location, the standard reference for past weather, and the Canadian Fire Weather Index (the same system Copernicus uses), computed by WorldFires from that data. Days after the fire run until the first rain.

Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service (ERA5)

Day	High	Min. humidity	Peak gust	Rain	Danger (FWI)
4 Aug	25.1 °C	13 %	44 km/h	0.0 mm	Very high 43
5 Aug after	26.7 °C	10 %	44 km/h	0.0 mm	Very high 44
6 Aug after	27.8 °C	13 %	49 km/h	0.0 mm	Very high 47
7 Aug after	28.7 °C	11 %	56 km/h	0.0 mm	Extreme 52
8 Aug after	27.5 °C	15 %	49 km/h	0.0 mm	Very high 48
9 Aug after	27.6 °C	17 %	43 km/h	0.0 mm	Very high 46
10 Aug after	28.2 °C	18 %	38 km/h	0.0 mm	Very high 44
11 Aug after	28.8 °C	16 %	38 km/h	0.1 mm	Very high 43
12 Aug after	27.5 °C	19 %	37 km/h	0.8 mm	High 32
13 Aug after	26.8 °C	19 %	44 km/h	0.0 mm	High 38
14 Aug after	25.1 °C	17 %	44 km/h	0.0 mm	High 38
15 Aug after	23.5 °C	18 %	42 km/h	0.0 mm	Very high 38
16 Aug after	22.9 °C	20 %	38 km/h	0.0 mm	High 38
17 Aug after	23.6 °C	16 %	36 km/h	0.0 mm	High 36

Before and after, from space

Drag the line to compare the same ground before the fire and after it.

↔

Before · 28 Jul 2025

After · 11 Aug 2025

Before After

If the day is cloudy, change the date: each satellite passes once a day. In false colour the burnt ground looks brown or red.

The smoke

CAMS · Copernicus

On 6 August 2025 the air beside the fire reached 42 µg/m³ of PM2.5. That day averaged 26: 1.7 times the WHO daily guideline (15).

PM2.5 peak42 µg/m³

Days over the guideline5 days

PM1043 µg/m³

Optical depth0.41

WHO 15

234567

Good Fair Moderate Poor Very poor Extremely poor

Particles from the Copernicus CAMS model at the centre of the perimeter; these are not measurements in each town. The pale bar is the worst hour, the solid one the daily average.

Open-Meteo.com (CC BY 4.0) · Copernicus Atmosphere Monitoring Service (CAMS)

Detections table · 84Every satellite heat detection, one by one, with time, satellite, power and coordinates.

⬇ Download CSV Times in UTC. Each detection is a 375 m pixel: a large fire yields hundreds per pass.

Date and time	Satellite	FRP (MW)	Lat	Lon

Other fires nearby

All fires in United States ›

Frequently asked questions

How long did the Gold fire last?: It burned between 4 August 2025 and 4 August 2025: 1 day, according to the start date recorded by United States agencies (MTBS / NIFC) and the heat detections seen by satellite.
How much area did it burn?: The official perimeter published by United States agencies (MTBS / NIFC) is 419 hectares (4.2 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?: The fire only entered San Bernardino (414 ha, 0.0 %).
What was the weather like?: During the fire the temperature reached 28.7 °C, humidity dropped to 10 % and gusts hit 56 km/h. The fire danger index (FWI) reached 52, class Extreme.
Where does this data come from?: From the official burnt perimeter of United States agencies (MTBS / NIFC, public domain), NASA FIRMS VIIRS hotspots and the administrative boundaries of United States. It is not an official report.

Where to verify it

A satellite detection is not an official report. Final figures and the fire’s status are published by each country’s emergency service.

Emergency number: 911

Satellite cross-check

NASA FIRMS ↗
NIFC · Fire maps ↗

Does something look wrong on this page?

This page is built from satellite data and official records, and it sometimes gets things wrong: the wrong dates, the wrong town, two fires merged into one, or something that was not a wildfire at all. If you know this fire first-hand (you live nearby, saw it, fought it or reported on it), tell us what really happened and we will check it.

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What really happened?

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We will only use your email to reply about this report. Privacy. This is not an emergency service: if there is a fire now, call 911.

Where this data comes from

The perimeter is official and in the public domain. For past years it comes from MTBS (Monitoring Trends in Burn Severity), run by the U.S. Geological Survey and the USDA Forest Service, which map it on Landsat and Sentinel-2 imagery. For the current and last year it comes from WFIGS at the National Interagency Fire Center (NIFC): incident perimeters mapped by fire crews, aircraft and imagery. Heat detections come from the VIIRS sensors aboard Suomi-NPP and NOAA-20, distributed by NASA FIRMS at 375 m resolution. County boundaries come from geoBoundaries ADM2 (Public Domain). The area per county is computed by WorldFires by crossing the perimeter with those boundaries, so it may differ slightly from official figures.

Where it burned